Treatment and prevention of reactive oxygen metabolite-mediated cellular damage

ABSTRACT

The present invention relates to a method for preventing and/or reducing cellular and tissue damage caused by reactive oxygen metabolites (ROMs) released by phagocytic or endothelial cells in response to various disease states or pathologies. The methods of the present invention are useful in preventing and treating a variety of disease states or pathological situations in which ROMs are produced and released. The methods of the present invention contemplate reducing ROM-mediated damage by reducing the production and release of ROMs.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to methods for treating and/orpreventing tissue and cell damage caused by reactive oxygen species inmammals. More specifically, the present invention relates to theprevention and/or reduction of tissue and cell damage through theadministration of histamine and histamine agonists.

[0002] The complete reduction of one molecule of O₂ to water is afour-electron process. Oxidative metabolism continually generatespartially reduced species of oxygen, which are far more reactive, andhence more toxic than O₂ itself. A one-electron reduction of O₂ yieldssuperoxide ion (O₂ ⁻); reduction by an additional electron yieldshydrogen peroxide (H₂O₂), and reduction by a third electron yields ahydroxyl radical (OH.), and a hydroxide ion. Nitrous oxide (NO), isanother interesting reactive oxygen metabolite, produced through analternative pathway. Hydroxyl radicals in particular are extremelyreactive and represent the most active mutagen derived from ionizingradiation. All of these species are generated and must be converted toless reactive species if the organism is to survive.

[0003] Particular cells of the immune system have harnessed the toxiceffects of ROMs as an effector mechanism. Professional phagocytes,polymorphonuclear leukocytes (neutrophils, PMN), monocytes, macrophages,and eosinophils function to protect the host in which they reside frominfection by seeking out and destroying invading microbes. Thesephagocytic cells possess a membrane-bound enzyme system which can beactivated to produce toxic oxygen radicals in response to a wide varietyof stimuli.

[0004] The “increased respiration of phagocytosis” (the respiratoryburst) was reported and thought to be a result of increasedmitochondrial activity providing additional energy for the processes ofphagocytosis. It was later shown that a non-mitochondrial enzymaticsystem produced the increased levels of oxygen metabolites since therespiratory burst continued even in the presence of mitochondrialinhibitors such as cyanide and antimycin A. In 1968, Paul and Sbarrashowed clearly that hydrogen peroxide was produced by stimulatedphagocytes and in 1973 Babior and co-workers established that superoxidewas a major product of the oxidase. (Paul and Sbarra, Biochim BiophysActa 156(1):168-78 (1968); Babior, et al., J Clin Invest 52(3):741-4(1973). It is now generally accepted that the enzyme is membrane bound,exhibits a preference for NADPH (K_(m)=45 μM) over NADH (K_(m)=450 μM),and converts oxygen to its one electron-reduced product, superoxide.

NADPH+H⁺+2O₂→NADP⁺+2H⁺2O₂ ⁻

[0005] The hydrogen peroxide arises from subsequent dismutation of thesuperoxide.

2O₂ ⁻+2H⁺→H₂O₂+O₂ ⁻

[0006] The enzyme activity is almost undetectable in resting(unstimulated) phagocytes, but increases dramatically upon stimulation.In patients with the rare genetic disorder chronic granulomatous disease(CGD), there is a severe predisposition to chronic recurrent infection.The neutrophils from these patients phagocytose normally but therespiratory burst is absent and NADPH oxidase activity (and radicalproduction) is undetectable, indicating that the oxidase and itsproduct, the reactive oxygen metabolites, have an important bactericidalfunction.

[0007] Neutrophilis and macrophages produce oxidizing agents to breakthrough the protective coats or other factors that protect phagocytosedbacteria. The large quantities of superoxide, hydrogen peroxide, andhydroxyl ions are all lethal to most bacteria, even when found in verysmall quantities.

[0008] While there are beneficial effects of these oxygen metabolites,it is clear that inappropriate production of oxygen metabolites canresult in severely deleterious effects. Several disease statesillustrate this point, including various inflammatory diseases,including rheumatoid arthritis, Crohn's disease, and Adult RespiratoryDistress Syndrome (ARDS). An effective method to reduce and/or minimizethe production and release of ROMs in patients suffering from a varietyof disparate diseases would be a great boon to medicine and service toreduce and eliminate a substantial amount of human suffering.

SUMMARY OF THE INVENTION

[0009] The present invention provides a novel method for inhibiting andreducing enzymatically produced ROM-mediated oxidative damage. Inaccordance with one aspect of the present invention, there is provided amethod for inhibiting and reducing enzymatically produced ROM-mediatedoxidative damage in a subject comprising the step of administering acompound effective to inhibit the production or release of enzymaticallyproduced reactive oxygen metabolites to a subject suffering from acondition caused or exacerbated by enzymatically produced ROM-mediatedoxidative damage.

[0010] In one embodiment, the reactive oxygen metabolites are releasedconstitutively. Alternatively, the reactive oxygen metabolites arereleased in response to a respiratory burst. In another embodiment ofthe present invention, the condition is selected from the groupconsisting of ARDS, ischemia or reperfusion injury, infectious disease,autoimmune or inflammatory diseases, and neurodegenerative diseases.

[0011] In another embodiment of the present invention, the compound isselected from the group consisting of histamine, H₂ receptor agonists,NADPH oxidase inhibitors, serotonin and serotonin agonists. Oneembodiment further comprising the step of administering an effectiveamount of a ROM scavenger. In the embodiment where a ROM scavenger isadministered, the step of administering the ROM scavenger results in ROMscavenger catalyzed decomposition of ROMs. In still another embodiment,the scavenger is selected from the group consisting of catalase,glutathione peroxidase, ascorbate peroxidase, superoxide dismutase,glutathione peroxidase, ascorbate peroxidase, vitamin A, vitamin E, andvitamin C.

[0012] In accordance with still another aspect of the present invention,there is provided a method for treating a subject suffering from adisease state wherein phagocyte produced ROM-mediated oxidative damagecan occur, comprising the steps of identifying a subject with acondition in which enzymatically generated ROMs released in response toa respiratory burst produce ROM-meditated oxidative damage andadministering a compound effective to inhibit the production or releaseof ROMs.

[0013] In one embodiment, the condition is selected from the groupconsisting of ARDS, ischemia or reperfusion injury, infectious disease,autoimmune or inflammatory diseases, and neurodegenerative diseases. Inanother embodiment, the step of administering the compound furthercomprises administering a compound selected from the group comprisinghistamine, H₂ receptor agonists, serotonin, serotonin agonists, andNADPH oxidase inhibitors. Another embodiment, further comprisingadministering an effective amount of a ROM scavenger. In the embodimentwhere a ROM scavenger is administered, the step of administering the ROMscavenger results in the reactive oxygen metabolites scavenger catalyzeddecomposition of reactive oxygen metabolites. In still anotherembodiment, the step of administering the reactive oxygen metabolitesscavenger further comprises administering a compound selected from thegroup consisting of catalase, superoxide dismutase, glutathioneperoxidase, and ascorbate peroxidase.

[0014] In accordance with still another aspect of the present invention,there is provided a pharmaceutical composition comprising apharmaceutically acceptable carrier, a compound effective to inhibit theproduction or release of enzymatically generated ROMs and a compoundeffective to scavenge ROMs. In one embodiment, the compound effective toinhibit the production or release of ROMs is selected from the groupconsisting of histamine, H₂ receptor agonists, serotonin, serotoninagonists, and NADPH oxidase inhibitors. In another embodiment, thecompound effective to scavenge ROMs is selected from the groupconsisting of catalase, glutathione peroxidase, ascorbate peroxidase,superoxide dismutase, glutathione peroxidase, ascorbate peroxidase,vitamin A, vitamin E, and vitamin C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] The present invention relates to compositions and methods forpreventing and/or reducing cellular and tissue damage caused by reactiveoxygen metabolites (ROMs) released by phagocytic or endothelial cells inresponse to various disease states or pathologies. The compositions andmethods of the present invention are useful in preventing and treating avariety of disease states or pathological situations in which ROMs areproduced and released. The compositions and methods of the presentinvention contemplate reducing ROM-mediated damage by reducing theproduction and release of ROMs.

[0016] A variety of reactive oxygen metabolites are produced in themonovalent pathway of oxygen reduction. These ROMs are enzymaticallyproduced by phagocytes such as monocytes and polymorphonuclearneutrophils (PMNs) and frequently released in a respiratory burst.Neutrophils also produce ROMs constitutively. The constitutiveproduction may contribute to ROM mediated cellular damage. Hydrogenperoxide and other ROMs play an important role in a host's immunologicaldefenses. Nevertheless, ROMs produced in excessive amounts or atinappropriate times or locations, act to damage a host's cells andtissues, and thus can be detrimental to the host.

[0017] The effects of ROM production are many faceted. ROMs are known tocause apoptosis in NK cells. ROMs are also known to cause anergy and/orapoptosis in T-cells. The mechanisms by which ROMs cause these effectsare not fully understood. Nevertheless, some commentators believe thatROMs cause cell death by disrupting cellular membranes and by changingthe pH of cellular pathways critical for cell survival.

[0018] It is one of the surprising discoveries of the present inventionthat compounds that reduce the amount of ROMs produced or released bysources within a subject can facilitate the treatment and recovery ofindividuals suffering from a variety of medical conditions. Theconditions contemplated as treatable under the present invention resultfrom a disparate number of etiological causes. Nevertheless, they sharea common feature in that their pathological conditions are either causedor exacerbated by enzymatically produced, ROM-mediated oxidative damage,caused by inappropriate and harmful concentrations of ROMs. Thus, theadministration of compounds that inhibit the production or release ofROMs, or scavenge ROMs, alone or in combination with other beneficialcompounds, provides an effective treatment for a variety of medicalconditions.

[0019] The present invention contemplates compounds and methods that areefficacious in treating a variety of medical conditions wherein ROMsplay an active, detrimental role in the pathological state of thedisease. Such conditions include but are not limited to: AdultRespiratory Distress Syndrome (ARDS); ischemia/reperfusion injury suchas stroke, myocardial infarction, complications of mechanicalventilation or septic shock; treatment of infectious diseases such ashepatitis C, acquired immunodeficiency syndrome (AIDS), or herpes virusinfection; various autoimmune or inflammatory disorders where ROMs arebelieved to play a detrimental role such as multiple sclerosis (MS) andrheumatoid arthritis, and Inflammatory Bowel Diseases such as Crohn'sdisease and ulcerative colitis; various neurodegenerative disease whereROMs are thought to contribute to the disease state, such as ALS,Alzheimer's disease, and Parkinson's disease; as well as other clinicalconditions wherein enzymatically produced ROMs can play an importantrole such as in radiation injury and cancer.

[0020] In a preferred embodiment, the present invention contemplatesusing various histamine and histamine-related compounds to achieve abeneficial reduction or inhibition of enzymatic ROM production andrelease or the net concentration thereof. The term “histamine” as usedherein incorporates a variety of histamine and histamine relatedcompounds. For example, histamine, the dihydrochloride salt form ofhistamine (histamine dihydrochloride), histamine diphosphate, otherhistamine salts, esters, or prodrugs, and H₂ receptor agonists are to beincluded. The administration of compounds that induce the release ofendogenous histamine from a patient's own tissue stores is also includedwithin the scope of the present invention. Such compounds include IL-3,retinoids, and allergens. Other ROM production and release inhibitorycompounds such as NADPH oxidase inhibitors like diphenlyeneiodonium arealso within the scope of the present invention. The use of serotonin and5HT agonists in the present invention is also contemplated.

[0021] The compositions and methods of the present invention furthercontemplate administrating a variety of ROM scavengers in conjunctionwith the ROM production and release inhibiting compounds describedabove. Known scavengers of ROMs include the enzymes catalase, superoxidedismutase (SOD), glutathione peroxidase and ascorbate peroxidase.Additionally, vitamins A, E, and C are known to have scavenger activity.Minerals such as selenium and manganese can also be efficacious incombating ROM-mediated damage. It is intended that the present inventioninclude the administration of the compounds listed and those compoundswith similar ROM inhibitor activity.

[0022] The compositions and methods of the present invention alsoprovide an effective means for preventing and/or inhibiting the releaseof enzymatically generated ROMs in excessive amounts or at inappropriatetimes or locations. One embodiment of the present invention alsoprovides compounds and methods for the treatment of a variety of diseasestates that are complicated by the detrimental release of ROMs within ahost or subject.

[0023] The administration of the compounds of the present invention canbe alone, or in combination with other compounds effective at treatingthe various medical conditions contemplated by the present invention.For example, histamine can be used to treat a patient suffering fromARDS in conjunction with mechanical ventilation methods used to provideadequate oxygenation of the blood. Further, the compounds of the presentinvention can be used with a variety of anti-coagulation drugsadministered by those of skill in the art, such as a tissue plasminogenactivator (TPA), when treating a stroke or acute myocardial infarction.Also, the compounds of the present invention, such as histamine, can beadministered with a variety of analgesics, anesthetics, or anxiolyticsto increase patient comfort during treatment.

[0024] The use of the ROM inhibiting or scavenging compounds of thepresent invention can be by any of a number of methods well known tothose of skill in the art. Such methods include parenteral deliverythrough subcutaneous, intravenous, intraperitoneal, or intramuscularinjection. The compounds can be administered in an aqueous solution withor without a surfactant such as hydroxypropyl cellulose. Dispersions arealso contemplated such as those utilizing glycerol, liquid polyethyleneglycols, and oils. Antimicrobial compounds can also be added to thepreparations. Injectable preparations can include sterile aqueoussolutions or dispersions and powders that can be diluted or suspended ina sterile environment prior to use. Carriers such as solvents ordispersion media contain water, ethanol polyols, vegetable oils and thelike can also be added to the compounds of the present invention.Coatings such as lecithins and surfactants can be used to maintain theproper fluidity of the composition. Isotonic agents such as sugars orsodium chloride can be added, as well as products intended to delayabsorption of the active compounds such as aluminum monostearate andgelatin. Sterile injectable solutions are prepared according to methodswell known to those of skill in the art and can be filtered prior tostorage and/or use. Sterile powders can be vacuum or freeze dried from asolution or suspension. Sustained or controlled release preparations andformulations are also contemplated by the present invention and arediscussed below. Any material used in the composition of the presentinvention should be pharmaceutically acceptable and substantiallynon-toxic in the amounts employed.

[0025] In another embodiment of the present invention, histamineadministration occurs by administration through inhalation. In thisadministration route, histamine can be dissolved in water or some otherpharmaceutically acceptable carrier liquid for inhalation, or providedas a dry powder, and then introduced into a gas or powder that is theninhaled by the patient in an appropriate volume so as to provide thatpatient with a measured amount of histamine.

[0026] Suitable infusion devices for use in the present inventioninclude syringe pumps, auto injector systems and minipumps. Exemplarydevices include the Ambulatory Infusion Pump Drive, Model 30, availablefrom Microject Corp., Salt Lake City, Utah, and the Baxa SyringeInfuser, available from Baxa Corporation, Englewood, Colo. Any devicecapable of delivering histamine in the manner described below can beused with the present invention.

[0027] The infusion devices of the present invention preferably have aneffective amount of histamine, histamine dihydrochloride, histaminephosphate, serotonin, a 5HT agonist, an H₂ receptor agonist or asubstance which induces the release of an effective therapeutic amountof endogenous histamine contained therein. The device can be pre-loadedwith the desired substance during manufacture, or the device can befilled with the substance just prior to use. Pre-filled infusion pumpsand syringe pumps are well known to those of skill in the art. Theactive substance can be part of a formulation which includes acontrolled release carrier, if desired. A controller is used with thedevice to control the rate of administration and the amount of substanceto be administered. The controller can be integral with the device or itcan be a separate entity. It can be pre-set during manufacture, or setby the user just prior to use. Such controllers and their use withinfusion devices are well known to those of skill in the art.

[0028] Controlled release vehicles are well known to those of skill inthe pharmaceutical sciences. The technology and products in this art arevariably referred to as controlled release, sustained release, prolongedaction, depot, repository, delayed action, retarded release and timedrelease; the words “controlled release” as used herein is intended toincorporate each of the foregoing technologies.

[0029] Numerous controlled release vehicles are known, includingbiodegradable or bioerodable polymers such as polylactic acid,polyglycolic acid, and regenerated collagen. Known controlled releasedrug delivery devices include creams, lotions, tablets, capsules, gels,microspheres, liposomes, ocular inserts, minipumps, and other infusiondevices such as pumps and syringes. Implantable or injectable polymermatrices, and transdermal formulations, from which active ingredientsare slowly released are also well known and can be used in the presentinvention.

[0030] In one embodiment, the compounds of the present invention areadministered through a topical delivery system. The controlled releasecomponents described above can be used as the means to delivery theactive ingredients of the present invention. A suitable topical deliverysystem comprises the active ingredients of the present invention inconcentrations taught herein, a solvent, an emulsifier, apharmaceutically acceptable carrier material, penetration enhancingcompounds, and preservatives. Examples of topically applied compositionsinclude U.S. Pat. Nos. 5,716,610 and 5,804,203, which are herebyincorporated by reference.

[0031] Controlled release preparations can be achieved by the use ofpolymers to complex or absorb the histamine. The controlled delivery canbe exercised by selecting appropriate macromolecule such as polyesters,polyamino acids, polyvinylpyrrolidone, ethylenevinyl acetate,methylcellulose, carboxymethylcellulose, and protamine sulfate, and theconcentration of these macromolecule as well as the methods ofincorporation are selected in order to control release of activecompound.

[0032] Hydrogels, wherein the histamine compound is dissolved in anaqueous constituent to gradually release over time, can be prepared bycopolymerization of hydrophilic mono-olefinic monomers such as ethyleneglycol methacrylate. Matrix devices, wherein the histamine is dispersedin a matrix of carrier material, can be used. The carrier can be porous,non-porous, solid, semi-solid, permeable or impermeable. Alternatively,a device comprising a central reservoir of histamine surrounded by arate controlling membrane can be used to control the release ofhistamine. Rate controlling membranes include ethylene-vinyl acetatecopolymer or butylene terephthalate/polytetramethylene etherterephthalate. Use of silicon rubber depots are also contemplated.

[0033] Controlled release oral formulations are also well known. In oneembodiment, the active compound is incorporated into a soluble orerodible matrix, such as a pill or a lozenge. Such formulations are wellknown in the art. An example of a lozenge used to administerpharmaceutically active compounds is U.S. Pat. No. 5,662,920, which ishereby incorporated by reference. In another example, the oralformulations can be a liquid used for sublingual administration. Anexample of pharmaceutical compositions for liquid sublingualadministration of the compounds of the present invention are taught inU.S. Pat. No. 5,284,657, which is hereby incorporated by reference.These liquid compositions can also be in the form a gel or a paste.Hydrophilic gums, such as hydroxymethylcellulose, are commonly used. Alubricating agent such as magnesium stearate, stearic acid, or calciumstearate can be used to aid in the tableting process.

[0034] For the purpose of parenteral administration, histamine orcompounds which induce endogenous histamine release can be combined withdistilled water, preferably buffered to an appropriate pH and havingappropriate (e.g., isotonic) salt concentrations. Histamine formulationscan be provided as a liquid or as a powder that is reconstituted beforeuse. They can be provided as prepackaged vials, syringes, or injectorsystems.

[0035] Histamine can also be provided in septum-sealed vials in volumesranging from about 0.5 to 100 ml for administration to an individual. Ina preferred embodiment, the vials contain volumes of 0.5, 1, 3, 5, 6, 8,10, 20, 50 and 100 ml. The vials are preferably sterile. The vials canoptionally contain an isotonic carrier medium and/or a preservative. Anydesired amount of histamine can be used to give a desired finalhistamine concentration. In a preferred embodiment, the histamineconcentration is between about 0.01 mg/ml and 100 mg/ml. Morepreferably, the histamine concentration is between about 0.1 and 50mg/ml. Most preferably, the histamine concentration is between about 1mg/ml and 10 mg/ml. At the lower end of the volume range, it ispreferred that individual doses are administered, while at the higherend it is preferred that multiple doses are administered.

[0036] In a preferred embodiment, transdermal patches, steady statereservoirs sandwiched between an impervious backing and a membrane face,and transdermal formulations, can also be used to deliver histamine andhistamine agonists. Transdermal administration systems are well known inthe art. Occlusive transdermal patches for the administration of anactive agent to the skin or mucosa are described in U.S. Pat. Nos.4,573,996, 4,597,961 and 4,839,174, which are hereby incorporated byreference. One type of transdermal patch is a polymer matrix in whichthe active agent is dissolved in a polymer matrix through which theactive ingredient diffuses to the skin. Such transdermal patches aredisclosed in U.S. Pat. Nos. 4,839,174, 4,908,213 and 4,943,435, whichare hereby incorporated by reference.

[0037] Present transdermal patch systems are designed to deliver smallerdoses over longer periods of time, up to days and weeks, whereas thepresent invention would specifically deliver an effective dose ofhistamine in a range of between about 2 and 60 minutes, depending uponthe dose, with a preferred dose being delivered within about 20-30minutes. These patches allow rapid and controlled delivery of histamine.A rate-controlling outer microporous membrane, or micropockets ofhistamine dispersed throughout a silicone polymer matrix, can be used tocontrol the release rate. Such rate-controlling means are described inU.S. Pat. No. 5,676,969, which is hereby incorporated by reference. Inanother preferred embodiment, the histamine is released from the patchinto the skin of the patient in about 20-30 minutes or less. In apreferred embodiment, the histamine is released from the patch at a rateof between about 0.025 mg to 0.3 mg per minute for a dose of betweenabout 0.2 mg and 5 mg per patch.

[0038] These transdermal patches and formulations can be used with orwithout use of a penetration enhancer such as dimethylsulfoxide (DMSO),combinations of sucrose fatty acid esters with a sulfoxide or phosphoricoxide, or eugenol. The use of electrolytic transdermal patches is alsowithin the scope of the present invention. Electrolytic transdermalpatches are described in U.S. Pat. Nos. 5,474,527, 5,336,168, and5,328,454, the entire contents of which are hereby incorporated byreference.

[0039] In another embodiment transmucosal patches can be used toadminister the active ingredients of the present invention. An exampleof such a patch is found in U.S. Pat. No. 5,122,127, which is herebyincorporated by reference. The described patch comprises a housingcapable of enclosing a quantity of therapeutic agent where the housingis capable of adhering to mucosal tissues, for example, in the mouth. Adrug surface area of the device is present for contacting the mucosaltissues of the host. The device is designed to deliver the drug inproportion to the size of the drug/mucosa interface. Accordingly, drugdelivery rates can be adjusted by altering the size of the contact area.

[0040] The housing is preferably constructed of a material which isnontoxic, chemically stable, and non-reactive with the compounds of thepresent invention. Possible construction materials include:polyethylene, polyolefins, polyamides, polycarbonates, vinyl polymers,and other similar materials known in the art. The housing can containmeans for maintaining the housing positioned against the mucosalmembrane. The housing can contain a steady state reservoir positioned tobe in fluid contact with mucosal tissue.

[0041] Steady state reservoirs for use with the compounds of the presentinvention will delivery a suitable dose of those compounds over apredetermined period of time. Compositions and methods of manufacturingcompositions capable of absorption through the mucosal tissues aretaught in U.S. Pat. No. 5,288,497, which is hereby incorporated byreference. One of skill in the art could readily include the compoundsof the present invention in these and related compositions.

[0042] The steady state reservoirs for use with the present inventionare composed of compounds known in the art to control the rate of drugrelease. In one embodiment, the transmucosal patch delivers a dose ofhistamine over a period of time from about 2 to 60 minutes. The steadystate reservoir contained within the housing carries doses of histamineand other ROM production and release inhibitory compounds in doses fromabout 0.2 to 5 mg per patch. Transdermal patches that can be worn forseveral days and that release the compounds of the present inventionover that period of time are also contemplated. The reservoirs can alsocontain permeation or penetration enhancers, as discussed above, toimprove the permeability of the active ingredients of the presentinvention across the mucosal tissue.

[0043] Another method to control the release of histamine is toincorporate the histamine into particles of a polymeric material such aspolyesters, polyamino acids, hydrogels, poly lactic acid, or ethylenevinylacetate copolymers.

[0044] Alternatively, instead of incorporating histamine into thesepolymeric particles, histamine is entrapped in microcapsules prepared,for example, by coacervation techniques, or by interfacialpolymerization, for example hydroxymethylcellulose orgelatin-microcapsules, respectively, or in colloidal drug deliverysystems, for example, liposomes, albumin microspheres, microemulsions,nanoparticles, and nanocapsules, or in macroemulsions. Such technologyis well known to those of ordinary skill in pharmaceutical sciences.

[0045] Preferably, the histamine is injected, infused, or released intothe patient at a rate of from about 0.025 to 0.2 mg/min. A rate of about0.1 mg/min is preferred. The histamine is preferably administered over aperiod of time ranging from about 1, 3 or 5 minutes to about 30 minutes,with an upper limit of about 20 minutes being preferred, such that thetotal daily adult dose of histamine ranges from between about 0.4 toabout 10.0 mg, with about 0.5 to about 2.0 mg being preferred. Histamineadministered over longer periods of time, i.e., longer than about 30minutes, has been found to result in decreased or lack of efficacy,while rapid administration over less than 1-3 minutes can cause morepronounced and serious side effects, which include anaphylaxis, heartfailure, bronchospasm, pronounced flushing, discomfort, increased heartrate and respiratory rate, hypotension, and severe headache.

[0046] In another embodiment, histamine, a H₂-receptor agonist, atapproximately 0.2 to 2.0 mg or 3-20 μg/kg, in a pharmaceuticallyacceptable form can be administered. ROM scavenging compounds can alsobe administered in combination with the ROM production and releaseinhibitory compounds described above.

[0047] The treatment can also include periodically boosting patientblood histamine levels by administering 0.2 to 2.0 mg or 3-20 μg/kg ofhistamine injected 1, 2, or more times per day over a period of one totwo weeks at regular intervals, such as daily, bi-weekly, or weekly inorder to establish blood histamine at a beneficial concentration suchthat ROM production and release is inhibited. The treatment is continueduntil the causes of the patient's underlying disease state is controlledor eliminated.

[0048] Administration of each dose of histamine can occur from once aday to up to about four times a day, with twice a day being preferred.Administration can be subcutaneous, intravenous, intramuscular,intraocular, oral, transdermal, intranasal, or rectal and can utilizedirect hypodermic or other injection or infusion means, or can bemediated by a controlled release mechanism of the type disclosed above.Any controlled release vehicle or infusion device capable ofadministering a therapeutically effective amount of histamine over aperiod of time ranging from about 1 to about 30 minutes can be used. Ina preferred embodiment, intranasal delivery is accomplished by using asolution of histamine in an atomizer or nebulizer to produce a fine mistwhich is introduced into the nostrils. For rectal delivery, histamine isformulated into a suppository using methods well known in the art.

[0049] Compounds that scavenge ROMs can be administered in an amount offrom about 0.1 to about 10 mg/day; more preferably, the amount is fromabout 0.5 to about 8 mg/day; more preferably, the amount is from about0.5 to about 8 mg/day; and even more preferably, the amount is fromabout 1 to about 5 mg/day. Nevertheless, in each case, the dose dependson the activity of the administered compound. The foregoing doses areappropriate for the enzymes listed above that include catalase,superoxide dismutase (SOD), glutathione peroxidase and ascorbateperoxidase. Appropriate doses for any particular host can be readilydetermined by empirical techniques well known to those of ordinary skillin the art.

[0050] Non-enzymatic ROM scavengers can be administered in amountsempirically determined by one of ordinary skill in the art. For example,vitamins A and E can be administered in doses from about 1 to 5000 IUper day. Vitamin C can be administered in doses from 1 μg to 10 gm perday. Minerals such as selenium and manganese can be administered inamounts from about 1 picogram to 1 milligram per day. These compoundscan also be administered as a protective or preventive treatment for ROMmediated disease states.

[0051] In addition to histamine, histamine dihydrochloride, histaminephosphate, other histamine salts, esters, congeners, prodrugs, and H₂receptor agonists, the use of serotonin, 5HT agonists, and compoundswhich induce release of histamine from the patient's own tissues is alsoincluded within the scope of the present invention. Retinoic acid, otherretinoids such as 9-cis-retinoic acid and all-trans-retinoic acid, IL-3and ingestible allergens are compounds that are known to induce therelease of endogenous histamine. These compounds can be administered tothe patient by oral, intravenous, intramuscular, subcutaneous, and otherapproved routes. The rate of administration should result in a releaseof endogenous histamine resulting in a blood plasma level of histamineof about 2 nmol/dl.

[0052] Administration of each dose of a compound which induces histaminerelease can occur from once per day to up to about four times a day,with twice per day being preferred. Administration can be subcutaneous,intravenous, intramuscular, intraocular, oral, or transdermal, and canincorporate a controlled release mechanism of the type disclosed above.Any controlled release vehicle capable of administering atherapeutically effective amount of a compound which induces histaminerelease over a period of time ranging from about one to about thirtyminutes can be used.

[0053] The following predictive examples teach the methods of thepresent invention and the use of the disclosed ROM production andrelease inhibiting compounds. These examples are illustrative only andare not intended to limit the scope of the present invention. Thetreatment methods described below can be optimized using empiricaltechniques well known to those of ordinary skill in the art. Moreover,artisans of ordinary skill would be able to use the teachings describedin the following examples to practice the full scope of the presentinvention.

EXAMPLES Adult Respiratory Distress Syndrome

[0054] Adult Respiratory Distress Syndrome (ARDS) is a descriptive termthat has been applied to many acute, diffuse infiltrative lung lesionsof diverse etiologies when they are accompanied by severe arterialhypoxemia. The most common cause of ARDS is sepsis, however, diffusepulmonary infections (e.g., viral, bacterial, fungal, orPneumecyctosus); aspiration (e.g., gastric contents with Mendelson'ssyndrome, water from near drowning); inhalation of toxins and irritants(e.g., chlorine gas, NO₂, smoke, high concentrations of oxygen);narcotic overdose pulmonary edema; non-narcotic drug effects (e.g.,nitrofurantoin); immunologic response to host antigens (e.g.,Goodpasture's syndrome); and other conditions can lead to ARDS. Althoughdifferent etiologies can lead to the pathological state known as ARDS,there are many common features present at the onset of respiratoryfailure.

[0055] The earliest sign of ARDS can come as an increase in respiratoryfrequency followed shortly by dyspnea. Arterial blood gas measurementsin the earlier periods of treatment can disclose a depressed P_(O2)despite a decreased P_(CO2) so that alveolar-arterial difference foroxygen is increased.

[0056] At this stage administration of oxygen results in a significantincrease in the arterial P_(O2). Physical examination can beunremarkable, although a few fine inspiratory rates can be audible.Radiographically, the lung fields can be clear or demonstrate onlyminimal and scattered interstitial infiltrates. With progression, thepatient becomes cyanotic and increasingly dyspneic and tachypneic. Ralescan become more prominent and easily heard throughout both the longfields along with regions of tubular breath sounds; the chest radiographdemonstrates diffuse, extensive bilateral interstitial and alveolarinfiltrates.

[0057] Regardless of the initiating process, ARDS is invariablyassociated with increased liquid in the lungs. It is a form of pulmonaryedema, although distinct from cardiogenic pulmonary edema becausepulmonary capillary pressure is not elevated. Since hydrostaticpressures are not elevated, there is increased permeability of thealveolocapillary membranes that occurs via direct chemical injury.Inhaled toxic gases or elements associated with sepsis, bacterialendotoxins (gram-negative bacteria) or exotoxins (gram-positivebacteria) that stimulate monocytic phagocytes, resident macrophages, andpolymorphonuclear leukocytes to adhere to endothelial surfaces andundergo a respiratory burst.

[0058] One ramification of the respiratory burst is the production ofROM mediated injury and the release of inflammation mediators such asleukotrienes, thromboxanes, and prostaglandins. The monocyticphagocytes, mainly macrophages in the alveoli and those lining thevasculature, also release oxidants, mediators, cytokines, and a seriesof degradative enzymes and peptides that directly damage endothelial andalveolar surfaces and cause polymorphonuclear leukocytes to releasetheir lysosomal enzymes. Initially, the injury to the alveolocapillarymembrane results in leakage of liquid, macromolecules, and cellularcomponents from the blood vessels into the interstitial space and, withincreasing severity, into the alveoli. Given the pathophysiology ofARDS, it should be noted that early administration of histamine canlessen the overall damage to the pulmonary system early-on in theprocess since such an administration reduces ROM production and release.Accordingly, reduction of ROM levels reduces ROM-mediated oxidativedamage to cellular and tissue structures.

[0059] The treatment of an individual suffering from ARDS is discussedbelow, using the methods and compounds of the present invention.

Example 1

[0060] A patient is first identified having an injury to the lungs thatwould indicate the possible on-set of ARDS. At this point or prior,administration of the ROM production and release inhibitory compounds ofthe present invention, such as histamine, is initiated. Histamine, aH₂-receptor agonist, is administered through injection into the subjectexperiencing or about to experience ARDS at approximately 5 μg/kg.Additionally, the ROM scavenging compound catalase is also administeredin combination with the histamine in an amount of 10 mg/day. The aboveprocedure is repeated until an objective regression of symptoms isobserved. In patients with complete responses, the frequency of therapyis reduced.

[0061] The reduction in the levels of ROM production and release ismaintained by periodic histamine administrations. This entailsadministering 5-20 μg/kg of histamine injected 2 times per day, toinhibit ROM production and release. The treatment is continued until thepulmonary physiology stabilizes and/or the causative agents of the ARDSare removed.

Ischemia/Reperfusion Injury

[0062] Ischemia/reperfusion injury following stroke (blockage of a bloodvessel, or rupture of a blood vessel in the brain) or acute myocardialinfarction (heart stops, and blood cannot be pumped) has a common themein that neutrophils when arrested in blood vessels become activated.This activation leads to the respiratory burst, or degranulationdiscussed above, resulting in the production and release of ROMs. Thesefree radicals cause local tissue damage that can lead to vascularleakage and edema, thereby exacerbating the clinical situation of thestroke or infarction. In the lungs, this neutrophil/ROM damage is amajor cause of acute respiratory distress syndrome (ARDS) following MI,mechanical ventilation and other states that can lead to low tissueblood flow/low oxygen tension situations. In the brain this can expandthe area of tissue destruction, leading to irreversible brain damage.Thus, a compound that could prevent or reduce ROM-mediated damage causedby phagocytes could significantly protect normal tissue fromdestruction. The prevention and/or treatment of an individual sufferingfrom ischemia or reperfusion injury are discussed below, using themethods and compounds of the present invention.

Stroke

[0063] Brain damage is often caused by the common abnormality called a“stroke.” Strokes are often caused either by a ruptured blood vesselthat allows hemorrhage into the brain or by the thrombosis of the majorarteries supplying the brain. In either case, loss of the blood supplyto brain tissue occurs. In addition to the loss of oxygen caused by aninterruption of blood flow to the brain, phagocytes in the damaged areaare often induced to produce a respiratory burst, causing the productionand release of ROMs. The resulting increase in the concentration of ROMsaugments brain tissue damage in addition to that caused by the lack ofblood flow and oxygen.

Example 2

[0064] A patient presenting the symptoms of stroke is treated withhistamine, which should be administered as soon as the diagnosis ofstroke is made. Early administration prevents the occurrence of ROMmediated damage in individuals who have yet to experience a full blownstroke. Administration of the compounds can occur before, during andafter the detection of stroke symptoms in the patient.

[0065] Histamine is injected subcutaneously in a sterile carriersolution into the patient experiencing or about to experience stroke at15 μg/kg per day, in a pharmaceutically acceptable form. The aboveprocedure is repeated daily for 5-7 days or until an objectiveregression of symptoms is observed.

Myocardial Infarction

[0066] Immediately after an acute coronary occlusion, blood flow ceasesin the coronary vessels beyond the occlusion except from small amountsof collateral flow from surrounding vessels. The area of muscle that haseither zero flow or reduced flow to the point where it cannot sustaincardiac function is said to be infarcted. Thus, this condition is knownas myocardial infarction (MI).

[0067] Soon after the onset of the infarction, small amounts ofcollateral blood seeps into the infarcted area, and this, combined withprogressive dilation of the local blood vessels, causes the area tobecome overfilled with stagnant blood. During this period of interruptedblood flow, professional phagocytes, polymorphonuclear leukocytes(neutrophils, PMN), monocytes, and macrophages become stimulated andproduce a respiratory burst leading to cardiac muscle damage.

[0068] Death can result from the myocardial infarction if the extent oftissue damage is not limited. Restoration of cardiac output is alsoessential for the survival of the patient. Removal of the blockage thatcaused the myocardial infarction and restoration of blood flow to thecardiac muscle are also essential. In addition to standard MI treatmentprotocols well known in the medical arts, the administration of tissueplasminogen activator can also be used to treat myocardial infarction.For reference, see U.S. Pat. Nos. 5,770,425, 5,612,029, and 5,424,198,which are hereby incorporated by reference. Further, the ROM productionand release inhibitory compounds of the present invention areadministered to minimize tissue damage caused by ROM release as a resultof the myocardial infarction.

Example 3

[0069] Histamine is administered to a patient presenting the symptoms ofan MI. Histamine should be administered as soon as the diagnosis of MIis made. Administration to individuals who have yet to experience a fullblown MI can also occur to prevent or reduce the magnitude ofROM-mediated damage if the MI comes to fruition. Administration iscontinued during and after the symptoms of myocardial infarction aredetected.

[0070] Histamine, a H₂-receptor agonist, at approximately 10 μg/kg/day,in a pharmaceutically acceptable form is introduced by subcutaneousinjection into a subject experiencing or about to experience MI. Theabove procedure is repeated daily for 7 days.

Subendocardial Myocardial Infarction

[0071] Myocardial infarction frequently occurs in the subendocardialmuscle even when the epicardial portions of the heart muscle remainuninfarcted. This form of infarction occurs especially when thediastolic arterial pressure is very low or when the diastolicintraventricular pressure is very high. Most of the blood flow into thesubendocardial arterial plexus occurs during diastole. Therefore, whenthe diastolic arterial pressure is very low—as occurs in patients whohave aortic regurgitation, patent ductus arterious, or to a lesserextent arteriosclerosis—one can expect a high incidence ofsubendocardial myocardial infarction.

Example 4

[0072] Histamine is administered to a patient presenting subendocardialmyocardial infarction, as described in Example 3. The administration ofthis compound results in the prevention of the release or production ofROMs that would have otherwise been released in response to thesubendocardial myocardial infarction disease state.

Mechanical Ventilation

[0073] Endotracheal intubation and positive-pressure mechanicalventilation have direct and indirect effects on several organ systems,including the lung and upper airways, the cardiovascular system, and thegastrointestinal system. A variety of pulmonary complications attendmechanical ventilation, but oxygen toxicity is particularly relevant tothe present invention. Oxygen toxicity is a potential complication whenan FiO₂ of 0.6 or higher is required for more than 72 hours. Thecondition is thought to result from the generation of ROMs in the lunginterstitium.

Example 5

[0074] Histamine is administered by intravenous injection to a patientundergoing mechanical ventilation. Histamine, a H₂-receptor agonist, isadministered through daily injections to a patient receiving mechanicalventilation therapy at approximately 10 μg/kg/dose, in apharmaceutically acceptable form. The administration is continued duringthe ventilation therapy or until the symptoms disappear.Diphenyleneiodonium, a NADPH oxidase inhibitor is also administered byintravenous injection.

[0075] The ROM inhibitory compound therapy is continued even afterventilation therapy has ceased, however, the frequency of ROM inhibitorycompound therapy is reduced. The histamine is administered bysubcutaneous injection 10 μg/kg/day for seven days.

Septic Shock

[0076] Circulatory shock, or the generalized inadequacy of blood flowthroughout the body, to the extent that tissue damage occurs bothbecause of a lack of oxygen and because of the generation of respiratorybursts, is often caused by physiological conditions where cardiac outputis insufficient, as discussed above. Occasionally, a patient can havenormal cardiac output, yet the person is in circulatory shock. This canresult from excessive metabolism of the body so that even a normalcardiac output is inadequate, or from abnormal tissue perfusion patternssuch that most of the cardiac output is passing through blood vesselsthat are not supplying the local tissues with nutrition. Theseconditions are seen most frequently in the type of shock called septicshock or blood poisoning.

[0077] Although there are many different varieties of septic shockbecause of the many different types of bacterial infection that cancause it, the different types share certain common features. Somefeatures often seen in septic shock are: high fever; markedvasodilatation throughout the body, especially in the infected tissues;high cardiac output caused by the vasodilatation and by the effects ofbacterial toxins on the body's metabolism; an increase in bloodviscosity perhaps caused by red cell agglutination; and the developmentof microclots in widespread areas of the body, called disseminatedintravascular coagulation.

[0078] In response to the bacterial infection and the increasing numberof bacteria and bacterial toxins, the professional phagocytes undergorespiratory burst, and produce and release large quantities of ROMs andsecondary cytokines such as tumor necrosis factor-alpha (TNF-α) andinterleukin-1 (IL-1). An example of secondary cytokine mediated celldamage is found in the Shwartz an Reaction, where neutrophil mediatedcell damage is thought to be activated by TNF and IL-1. Imamura S, etal., “Involvement of tumor necrosis factor-alpha, interleukin-1 beta,interleukin-8, and interleukin-1 receptor antagonist in acute lunginjury caused by local Shwartzman reaction” Pathol Int. 47(1):16-24(1997). This ROM and cytokine release augments the bacteria-mediatedcell damage as these potent chemical compounds are disseminatedthroughout the body. Although released as a defensive measure by thecells of the immune system, the ROMs result in ROM-mediated cell damageand the secondary cytokines cause a rapid deterioration of the patient,resulting often in death.

Example 6

[0079] A patient presenting a systemic bacterial infection is selectedfor treatment with the compounds of the present invention. In the earlystages of septic shock, the patient may not present signs of circulatorycollapse. As the infection becomes more severe, however, the circulatorysystem can become involved in the bacterial infection.

[0080] Histamine administration occurs as soon as the diagnosis ofseptic shock is made. Administration of histamine to individuals whohave yet to experience a full blown septic shock can also occur toprevent or reduce the magnitude of ROM-mediated damage and exacerbationof the shock state by the release of TNF-α or IL-1 if septic shock comesto fruition. Administration is continued during and after the symptomsof septic shock are detected.

[0081] Initially, histamine, at approximately 7 μg/kg, in apharmaceutically acceptable form is injected subcutaneously in a sterilecarrier solution into subjects experiencing or about to experienceseptic shock. The above procedure is repeated until an objectiveregression of symptoms is observed.

Treatment of Infectious Diseases

[0082] The production and release of ROMs is an active and importantpart of any immunological response to an invading pathogenic organism.The initial production and release of ROMs can serve to assist thebody's immune system in destroying invading pathogens and to assist inthe elimination of host cells that have been infected with an invadingorganism. Nevertheless, an excessive production of ROMs can pose aproblem of its own to the host organism.

[0083] In certain chronic infectious diseases, the constitutiveproduction and release of ROMs cause more harm to host cells than thebenefits derived from the antibacterial or antiviral properties of ROMproduction. In those situations, patients who are combating pathogenicinfections will benefit from the inhibition of ROM production andrelease. Accordingly, administration of the present invention'scompounds are contemplated as efficacious for the treatment of variousinfectious diseases.

Hepatitis C

[0084] Hepatitis C (HCV) has become a significant health threatthroughout the world. HCV is an RNA virus that specifically infects theliver. Chronic infection leads to liver malfunction, cirrhosis, andeventually death. Acute hepatitis C infections, however, are usuallyassociated with subclinical disease, with only approximately one quarterof acute cases resulting in jaundice. When acute disease occurs, generalsymptoms of hepatitis are apparent, such as malaise, anorexia, nausea,and occasionally pain in the right upper abdomen. There are few otherphysical signs of disease, with hepatomegaly and splenomegaly occurringin only a small proportion of patients.

[0085] In an HCV infected patient, the main immune response compriseslymphocytic cells such as NK cells, followed by T-cells, and much of thedamage to liver tissue is due both to the virus and to the patient's owninflammatory response in the liver by phagocytic cells. Liver damagecaused by phagocytic cells results, in part, from ROM production. Thepresence of the ROMs can also block, inhibit or prevent lymphocyticcells from effectively dealing with the source of the infection. Thus,the ROM serve to harm the infected individual through two pathways. Acompound like histamine, that blocks ROM production, would serve toeliminate or inhibit direct ROM mediated damage, and also function tofacilitate and enhance NK cells and T-cells so that they respond betterto the viral infection. The prevention and/or treatment of an individualsuffering from an HCV infection are discussed below, using the methodsand compounds of the present invention.

[0086] Although HCV infection can present a variety of clinical symptomsby which to identify the infection, an accurate diagnosis can only beachieved by assaying for specific markers of the virus. Initially,serodiagnosis can be accomplished by monitoring for the presence ofcirculating antibodies to HCV using commercially availableimmunoscreening kits. The time for seroconversion is variable andgenerally occurs within 7 to 31 weeks after infection from transfusion.A variety of additional tests can be performed on subjects presenting apositive ELISA reaction. One such test is the RIBA, which comprises theindividual antigens separated on a paper strip (ven der Poel, C. L., etal., Lancet 337:317-319 (1991); hereby incorporated by reference).Another method used to determine viral load is via PCR. One such methodutilizes reverse transcriptase PCR to amplify HCV RNA. (See, Perez-RuizM, et al., “Determination of HCV RNA concentration by directquantitation of the products from a single RT-PCR,” J Virol Methods69:113-24 (1997); hereby incorporated by reference).

[0087] Currently, the only available treatment for chronic HCV infectionis alpha-interferon (α-IFN) which has been shown to be minimallyeffective in patients with HCV. Unfortunately, α-IFN therapy requirescontinuous treatment, with approximately 70% of α-IFN respondingpatients relapsing to a more progressive disease state. Moreover, thereare a number of side effects of interferon therapy known, such as 60% to80% of patients experiencing flu-like symptoms, increasing levels ofirritability, fatigue, depression, anorexia, nausea, rashes, alopecia,thrombocytopenia, and leukopenia.

[0088] The compounds of the present invention are administered throughthe routes of administration discussed above in the doses describedabove, either alone or in conjunction with an HCV antiviral compound.The administration of these compounds results in the prevention ofrelease or production of ROMs that would have otherwise been released inresponse to the HCV infection. The compounds of the present inventionare administered to a patient presenting the symptoms of HCV infection.The ROM production and release inhibiting compounds of the presentinvention should be administered as soon as appropriate following thediagnosis of HCV infection.

Example 7

[0089] An individual suffering from an HCV infection is identified. Upondiagnosis of an HCV infection, a treatment course should commence. Inaddition to the administration of an active anti-HCV compound, theadministration of the compounds of the present invention is efficaciousin treating HCV infected individuals. For example, histamine, atapproximately 12 μg/kg/day in a pharmaceutically acceptable form isadministered through a controlled release vehicle, such as asuppository, into a subject experiencing an HCV infection.

[0090] The above procedure is continued for twelve to eighteen months toresolve the viral infection. The ROM scavenging compound vitamin E isalso administered in combination with the histamine injection, in anamount of 5 mg/day. The treatment is continued until the patient'sunderlying viral infection is controlled or eliminated.

Autoimmune/Inflammatory Disorders

[0091] The etiology of several autoimmune disorders share the commonfeature of an over-reactive inflammatory response as a contributingfactor to the pathology of the disease. A common denominator of thisshared feature is the release of ROMs by phagocytic cells at the site oftissue injury. The neurodegenerative disease multiple sclerosis (MS)illustrates this situation. In MS, autoreactive T-cells begin to attackthe myelin basic protein found in the protective myelin sheath ofneurons. The initial insult is followed by worsening of the pathologycaused by phagocytes and an over-reactive inflammatory response leadingto further neuronal damage caused by the release of ROMs. Thus, thepresence of ROMs accelerates neuronal damage and contributes to nervoussystem damage. A compound such as histamine could significantly reducethe ROM-mediated damage and allow for other treatments using cytokinessuch as gamma or beta interferons, and eliminate or change the need forsteroidal treatments that can have other problematic effects. Histamineis used alone or in combination in this situation.

Multiple sclerosis (MS)

[0092] The compounds of the present invention are administered to apatient presenting the symptoms of MS. They can be administered alone orin conjunction with other compounds efficacious in treating orcontrolling the MS disease state. The administration of these compoundsresults in the prevention of release or production of ROMs that wouldhave otherwise been released in response to the MS disease state. TheROM production and release inhibiting compounds of the present inventionshould be administered as soon as the diagnosis of MS is made.Administration is continued during and after the hallmarks of the MSdisease state are detected.

Example 8

[0093] Histamine, a H₂-receptor agonist, is administered to a patientdiagnosed as suffering from MS in a dose of 7:g/kg in a pharmaceuticallyacceptable form. Initially, the histamine is injected intramuscularly ina sterile carrier solution. The ROM scavenging compound superoxidedismutase is also administered at 7 mg/day. Subsequent treatments areadministered through an implanted infusion device that provides a doseof histamine at 15 μg/kg/day. Implantation of the infusion device isperformed using standard techniques well known in the art.

[0094] The above-described treatment is continued until an objectiveregression of symptoms is observed. New infusion devices are implantedto replace those that expend their histamine supply. In the event thesubject presents an increase in neurodegeneration, periodic boosting ofthe histamine levels is achieved by administering additional histaminedoses in 2 μg/kg doses by inhalation over a period of 5 times per day tocontrol ROM production and release and to prevent additional ROMmediated neurodegenerative damage. The treatment is continued for thelife of the patient.

Rheumatoid arthritis

[0095] Rheumatoid arthritis is another autoimmune pathology that beginswith local tissue damage in the joints that leads to further tissuedamage mediated by autoreactive T-cells and followed by infiltration ofpro-inflammatory cells like phagocytes which increase the damage byreleasing ROMs. Much of the ROM free radical damage could be preventedby treating with a compound like histamine to block phagocyte derivedROMs.

[0096] The compounds of the present invention are administered throughthe routes of administration discussed above in the doses describedabove, either alone or in conjunction with other compounds efficaciousin treating or controlling rheumatoid arthritis. The administration ofthese compounds results in the prevention of release or production ofROMs that would have otherwise been released in response to therheumatoid arthritis disease state. The compounds of the presentinvention are administered to a patient presenting the symptoms ofrheumatoid arthritis. The ROM production and release inhibitingcompounds of the present invention should be administered as soon as thediagnosis of rheumatoid arthritis is made. Administration is continuedduring and after the hallmarks of the rheumatoid arthritis disease stateare detected.

Example 9

[0097] Histamine, a H₂-receptor agonist, is administered to a patientdiagnosed with arthritis in a dose approximately 8 μg/kg, in apharmaceutically acceptable form. The histamine is initially injectedintravenously in a sterile carrier solution into a subject sufferingfrom rheumatoid arthritis. Thereafter, the histamine is administeredtransdermally in the form of a cream to those sites of the subject'sbody experiencing arthritis.

[0098] Application of the cream is repeated until a sustained objectiveregression of symptoms is observed. The therapy is continued even aftera partial response is observed. In patients with complete responses, thefrequency of therapy can be reduced to weekly administrations.

[0099] The treatment also includes periodically boosting patient bloodhistamine levels by administering a 8 μg/kg dose of histamine injectedintramuscularly, at regular weekly intervals. The treatment is continueduntil the causes of the patient's underlying rheumatoid arthritisdisease state are controlled or eliminated.

Inflammatory Bowel Disease

[0100] Inflammatory bowel disease (IBD) is a general term for a group ofchronic inflammatory disorders of unknown cause involving thegastrointestinal (GI) tract. Crohn's disease and ulcerative colitis areboth chronic inflammatory disorders that fall within the rubric of IBD.Both diseases have pronounced inflammation in the small intestinalmucosal tissue that can extend to other layers of the organ. Phagocyticcells are the primary drivers of the inflammatory reaction. As thesecells release ROMs in response to the inflammation, the intestinalmucosa is damaged, leading to potentially serious consequences for thepatient, including sepsis. A compound that prevents the production andrelease of ROMs could significantly impact on the pathogenesis of thesediseases.

[0101] The compounds of the present invention are administered throughthe routes of administration discussed above in the doses describedabove, either alone or in conjunction with other compounds efficaciousin treating or controlling IBD. The compounds of the present inventionare administered to a patient presenting the symptoms IBD. The ROMproduction and release inhibiting compounds of the present inventionshould be administered as soon as the diagnosis of IBD is made.Administration is continued during and after the hallmarks of the IBDstate are detected.

Example 10

[0102] Histamine, a H₂-receptor agonist, is administered to a patientpresenting the symptoms of IBD. Histamine is administered rectally atapproximately 20:g/kg/dose in a pharmaceutically acceptable form, in theform of a suppository.

[0103] The above procedure is repeated daily until an objectiveregression of symptoms is observed. The therapy is continued even aftera partial response is observed. In patients with complete responses, thefrequency of therapy can be reduced to weekly administrations.

[0104] The treatment can also include periodically boosting patientblood histamine levels by administering 10 μg/kg/day of histamineinjected subcutaneously at regular bi-weekly intervals. The treatment iscontinued until the causes of the patient's underlying IBD state arecontrolled or eliminated.

Neurodegenerative Diseases

[0105] ROM mediated cellular damage can be relevant to a number ofneurodegenerative diseases such as ALS, Parkinson's disease, andAlzheimer's. The production and release of ROMs can cause or exacerbatethe neurodegeneration of these diseases. Accordingly, the administrationof the ROM production and release inhibiting compounds of the presentinvention are contemplated as being safe and effective for the treatmentof a wide range of neurological disorders in which ROM mediated cellulardamage plays a clinical role.

Amyotrophic Lateral Sclerosis (Lou Gehrig's disease)

[0106] Amyotrophic lateral sclerosis (ALS) is also called Lou Gehrig'sdisease. It is a fatal disorder characterized by progressivedegeneration of the motor cells in the spinal cord and brain (centralnervous system), which inhibits nerve impulses from being sent to themuscles. Eventually, a person who has ALS experiences muscle weaknessand wasting, particularly of the muscles used to move the arms and legsand muscles involved in speech, swallowing, and breathing. The cause isunknown and there currently is no cure for ALS.

[0107] It appears that ALS can be caused by complex inheritance,including both genetic and environmental factors. So far, one gene hasbeen identified which is involved in the development of ALS in somefamilies showing autosomal dominant inheritance. The gene is calledsuperoxide dismutase 1 (SOD1), which is located on chromosome 21q22.

[0108] SOD1 is a member of a family of metalloenzymes characterized byan ability to dismutate O₂ ⁻, i.e., to catalyze the conversion of O₂ ⁻,the product of spontaneous and enzyme-catalyzed oxidation, into H₂O₂ andO₂. Behaving as a reductant or oxidant, O₂ ⁻ gives rise to reactivemolecules that can injure cells by a variety of mechanisms.

[0109] In view of this genetic link between ALS and the ROM pathway, thepresent invention contemplates utility in treating ALS. The symptoms ofALS include: tripping and falling, loss of motor control in hands andarms, difficulty speaking, swallowing and/or breathing, persistentfatigue, and twitching and cramping, sometimes quite severely. ALSstrikes in mid-life. These symptoms are caused by the loss of motorneurons resulting in muscle weakness and wasting, and paralysis.

Example 11

[0110] A patient presenting symptoms of ALS is treated by administeringthe compounds of the present invention as soon as the diagnosis of ALSis made. The treatment is initiated by administering histamine using asublingual composition at 5 μg/kg/day, in a pharmaceutically acceptableform, that is ingested orally by the subject suffering from ALS. Thehistamine is administered in conjunction with other compoundsefficacious in treating or controlling ALS.

[0111] Following the injection, the patient is administered histamine at5 mg/day in conjunction with vitamin A at 3000 IU/day, vitamin C at 1000mg/day, vitamin E at 600 IU/day, selenium at 50 μg/day and manganese at25 μg/day. These components can be formulated into a tablet for ease ofadministration.

[0112] The above procedure is repeated until an objective regression ofsymptoms is observed. The therapy can be continued even after a partialresponse is observed. In the event symptoms of ALS increase, the patientis to receive periodic boostings of histamine levels by theadministration of 5 μg/kg/day of histamine by nasal administration atregular two week intervals. The treatment is continued until the causesof the patient's underlying ALS state are controlled or eliminated, orfor the life of the patient.

Alzheimer's disease

[0113] In Alzheimer's disease, the usually highly ordered nerve cells ofthe brain become extremely disorganized, and form neurofibrillarytangles. Dementia develops as the extent of neurofibrillary tanglesincrease. The cause of Alzheimer's disease is unknown. Senile plaques,accumulations of cellular debris surrounding a central core ofbeta-amyloid peptide, can play a role. Beta-amyloid peptide was firstidentified in the 1980's, some 70 years after Alzheimer identifiedsenile plaques. For reasons that remain unclear, beta-amyloidaccumulates in the brain tissue of people with Alzheimer's andpresumably plays a role in destroying it.

[0114] Alzheimer disease (AD) is a clinical-neuropathological diagnosis.Affected individuals have slowly progressive dementia, gross cerebralcortical atrophy by neuroimaging studies and microscopic A Beta amyloidneuritic plaques, intraneuronal neurofibrillary tangles, and amyloidangiopathy at postmortem examination. The numbers of plaques and tanglesmust exceed those found in non-demented age-matched controls, andguidelines exist for these quantitative changes. The plaques shouldstain positively with A Beta amyloid antibodies and negative for prionantibodies.

[0115] The clinical diagnosis of AD (prior to autopsy confirmation) iscorrect about 80-90% of the time. AD typically begins with subtle andpoorly recognized failure of memory. Slowly, over a period of years, thememory loss becomes more severe and eventually incapacitating. Othercommon symptoms include confusion, poor judgment, language disturbance,agitation, withdrawal, and hallucinations. Some patients can developseizures, Parkinsonian features, increased muscle tone, myoclonus,incontinence, and mutism. Death usually results from general inanition,malnutrition, and pneumonia. The typical clinical duration of thedisease is 8-10 years with a wide-range of 1-25 years.

[0116] It has been reported that the ingestion of anti-oxidants,compounds that promote the metabolism of ROMs to less reactive formsonce they are synthesized and released, have had a positive effect ofAlzheimer's patients. For example, Czech researchers gave theantioxidant drug selegiline to 173 people with mild to moderateAlzheimer's disease. After six months, their memory improvedsignificantly. In another study, selegiline enhanced the benefits oftacrine (Cognex), one of the two drugs currently approved forAlzheimer's treatment. (Kawas, C. et al. “Treating Alzheimer's Disease:Today and Tomorrow,” Patient Care (Nov. 15, 1996) pp. 62-83). It shouldbe noted, however, that this report only addresses ROMs after they aresynthesized and released. In view of the correlation betweenanti-oxidants and the Alzheimer's disease state, the compounds of thepresent invention are contemplated as having utility in the treatment ofAlzheimer's disease by preventing or inhibiting the formation andrelease of ROMs.

Example 12

[0117] A patient presenting symptoms of AD is treated by administeringthe compounds of the present invention as soon as the diagnosis of AD ismade. Histamine, a H₂-receptor agonist, at a 5 μg/kg/dose, in apharmaceutically acceptable form is injected subcutaneously in a sterilecarrier solution into the subject. The histamine is administered inconjunction with other compounds efficacious in treating or controllingAD and known to those of ordinary skill in the art.

[0118] The above procedure is repeated until an objective regression ofsymptoms is observed. The treatment also include periodically boostingpatient blood histamine levels by administering 5 μg/kg/day of histamineat regular weekly intervals. The treatment is continued until theneurodegeneration responsible for the pathological condition of AD iscontrolled or eliminated, or for the life of the patient.

Parkinson's Disease

[0119] Parkinson's disease (PD), which is also known as paralysisagitans, results almost invariably from widespread destruction of thesubstantia nigra but is often associated also with lesions of the globuspallidus and other related areas. It is characterized by (1) rigidity ofthe musculature either in widespread areas of the body or in isolatedareas, (2) tremor at rest of the involved areas in most but not allinstances, and (3) a serious inability to initiate movement, calledakinesia.

[0120] Certain commentators have seen oxidative stress as a possiblecause of PD. Oxidative stress can play an important role in the creationof the Parkinson's disease state. Recently, the monoamine oxidase-Binhibitor L-deprenyl (Selegiline), a drug effective in the treatment ofPD and possibly Alzheimer's disease, was shown to induced rapidincreases in NO production in brain tissue and cerebral vessels.Vasodilatation was produced by endothelial NO-dependent as well asNO-independent mechanisms in cerebral vessels. The drug also protectedthe vascular endothelium from the toxic effects of amyloid-beta peptide.These novel actions of selegiline can protect neurons from ischemic oroxidative damage and suggest new therapeutic applications for L-deprenylin vascular and neurodegenerative diseases. Thomas et al, Neuroreport,9(11):2595-600 (1998). The efficacy of this compound supports the roleoxidative stress in the Parkinson's disease state.

[0121] In view of these observations, the compounds of the presentinvention are contemplated as an effective treatment of PD, either whenused alone or when the compounds of the present invention are usedcombination with other PD treatments.

Example 13

[0122] A patient presenting symptoms of PD is treated by administeringthe compounds of the present invention as soon as the diagnosis of PD ismade. Histamine, a H₂-receptor agonist, at 5 μg/kg/day, in apharmaceutically acceptable form is given by a transmucosal patch tosubjects suffering from PD. The histamine is administered in conjunctionwith other compounds efficacious in treating or controlling PD that arewell known in the art.

[0123] The therapy can be continued even after a partial response hasbeen observed. In patients with complete responses, the frequency oftherapy is reduced to weekly applications of histamine with transmucosalpatches when an objective regression of symptoms is observed.

Other Disease States Radiation Injury

[0124] Ionizing radiation is a harmful form of energy that damagestissue through the action of charged particles. Damage can result totissues exposed to ionizing radiation through the effect of the energyon water, oxygen, and other molecules with the formation of ROMs, suchas free hydroxyl radicals and other highly reactive oxygen species.Moreover, tissue damage and destabilization of homeostatic equilibriumdue to overexposure to radiation can result in a systemic respiratoryburst from professional phagocytes. This burst results in a release ofROMs causing tissue damage.

Example 14

[0125] A patient exposed to toxic levels of ionizing radiation istreated by administering the compounds of the present invention at thetime of treatment with an appropriate therapy or a diagnosis ofradiation toxicity. Histamine, a H₂-receptor agonist, at 17 μg/kg, isinjected subcutaneously in a pharmaceutically acceptable form intosubjects suffering from radiation toxicity. The histamine isadministered in conjunction with other compounds efficacious in treatingor controlling radiation poisoning that are well known to those of skillin the art.

[0126] The above procedure is repeated until an objective regression ofsymptoms is observed. The therapy is continued even after a partialresponse has been observed. In patients with complete responses, thefrequency of therapy is reduced.

[0127] The treatment can also include periodically boosting patientblood histamine levels by administering 5 μg/kg of histamine injectedonce per day over a period of one to two weeks at regular intervals,such as daily, so that ROM production and release is inhibited.

Conclusion

[0128] We have discovered that the administration of compounds thatinhibit the production and release of ROMs is instrumental in treatingand preventing ROM mediated cell and tissue damage. The detrimentaleffects of unwanted ROMs are removed when the compounds of the presentinvention are administered in accordance with the methods taught herein.Further, the administration of ROM scavengers can assist in reducing thenegative effects of unwanted ROM production.

[0129] Finally, the forgoing examples are not intended to limit thescope of the present invention, which is set forth in the followingclaims. In particular, various equivalents and substitutions will berecognized by those of ordinary skill in the art in view of theforegoing disclosure, and these are contemplated to be within the scopeof the present invention.

What is claimed is:
 1. A method for inhibiting and reducingenzymatically produced ROM-mediated oxidative damage in a subjectcomprising the steps of: identifying a subject suffering from acondition caused or exacerbated by enzymatically produced ROM-mediatedoxidative damage; and administering a compound effective to inhibit theproduction or release of enzymatically produced reactive oxygenmetabolites to said subject, wherein the compound is selected from thegroup consisting of histamine, H₂ receptor agonists, NADPH oxidaseinhibitors, serotonin and serotonin agonists.
 2. The method of claim 1 ,wherein the reactive oxygen metabolites are released constitutively. 3.The method of claim 1 , wherein the reactive oxygen metabolites arereleased in response to a respiratory burst.
 4. The method of claim 1 ,wherein said condition is selected from the group consisting of ARDS,ischemia or reperfusion injury, infectious disease, autoimmune orinflammatory diseases, and neurodegenerative diseases.
 5. The method ofclaim 1 further comprising the step of administering an effective amountof a ROM scavenger.
 6. The method of claim 5 , wherein the step ofadministering said ROM scavenger results in ROM scavenger catalyzeddecomposition of ROMs.
 7. The method of claim 5 , wherein the scavengeris selected from the group consisting of catalase, glutathioneperoxidase, ascorbate peroxidase, superoxide dismutase, glutathioneperoxidase, ascorbate peroxidase, vitamin A, vitamin E, and vitamin C.8. A method for treating a subject suffering from a disease statewherein phagocyte produced, ROM-mediated oxidative damage can occur,comprising the steps of: identifying a subject with a condition in whichenzymatically generated ROMs released in response to a respiratory burstproduce ROM-meditated oxidative damage; and administering a compoundeffective to inhibit the production or release of ROMs, wherein the stepof administering said compound further comprises administering acompound selected from the group consisting of histamine, H₂receptoragonists, serotonin, serotonin agonists, and NADPH oxidase inhibitors.9. The method of claim 8 , wherein said condition is selected from thegroup consisting of ARDS, ischemia or reperfusion injury, infectiousdisease, autoimmune or inflammatory diseases, and neurodegenerativediseases.
 10. The method of claim 9 , further comprising administeringan effective amount of a ROM scavenger.
 11. The method of claim 10 ,wherein the step of administering said ROM scavenger results in thereactive oxygen metabolites scavenger catalyzed decomposition ofreactive oxygen metabolites.
 12. The method of claim 11 , wherein thestep of administering said reactive oxygen metabolites scavenger furthercomprises administering a compound selected from the group consisting ofcatalase, superoxide dismutase, glutathione peroxidase, and ascorbateperoxidase.